Improve accessibility (part 4) (#4408)

* fix(dropdown_menu): Keyboard navigation

* fix(icon_button): Add aria-pressed attribute

* fix(privacy_dropdown): Make accessible

* fix(emoji_picker_dropdown): Make accessible

* fix(icon_button): Support tabIndex

* fix(actions_modal): Remove icon from tab order

* fix(dropdown_menu): Add role=group

* fix(setting_toggle): Toggle via space key

* fix(dropdown_menu): Remove redundant handling of Space key

* fix(emoji_picker_dropdown): Remove redundant Space key handling

* fix(privacy_dropdown): Remove redundant Space key handling

* fix(status): Switch to article and add aria-posinset, aria-setsize

* fix(status_list): Use role=feed and pass more ARIA props to Status

* chore(eslint): jsx-a11y/role-supports-aria-props

app/javascript/mastodon/components/icon_button.js

@@ -12,12 +12,14 @@ export default class IconButton extends React.PureComponent {
     onClick: PropTypes.func,
     size: PropTypes.number,
     active: PropTypes.bool,
+    pressed: PropTypes.bool,
     style: PropTypes.object,
     activeStyle: PropTypes.object,
     disabled: PropTypes.bool,
     inverted: PropTypes.bool,
     animate: PropTypes.bool,
     overlay: PropTypes.bool,
+    tabIndex: PropTypes.string,
   };
 
   static defaultProps = {
@@ -26,6 +28,7 @@ export default class IconButton extends React.PureComponent {
     disabled: false,
     animate: false,
     overlay: false,
+    tabIndex: '0',
   };
 
   handleClick = (e) =>  {
@@ -73,10 +76,12 @@ export default class IconButton extends React.PureComponent {
         {({ rotate }) =>
           <button
             aria-label={this.props.title}
+            aria-pressed={this.props.pressed}
             title={this.props.title}
             className={classes.join(' ')}
             onClick={this.handleClick}
             style={style}
+            tabIndex={this.props.tabIndex}
           >
             <i style={{ transform: `rotate(${rotate}deg)` }} className={`fa fa-fw fa-${this.props.icon}`} aria-hidden='true' />
           </button>